Method of producing metal lath



April 1, 1941. H. M. GERSMAN METHOD OF PRODUCING METAL LATH Filed Ma 29, 1939 7 I lN VE NTOR I firm Qexswzarz ATTORNEY Patented Apr. 1, 1941 UNITED STATES PATEN METHOD or raonucmc. METALLATl-l Harvey M. Gersman, New York, N. Y., assignor to Fen-ex Corporation, New York, N. Y., acorporation of Delaware Application May 29, 1939, Serial No 216,316

(01. 164-65) i H rows being in sta gered r brakqoin f relation;

with respect to the'slits lli offinterinediatefrows I Y and preferably being shorter' mamas latter. From the rolls I [and lIfjthejslieetpaSss toaf pair of forming rolls lland 118;? one of' which is Claims.

This invention relates to improvements in metal lath and to a method of expanding metal which is suitable for the production of such lath.

Various of the processes heretofore proposed for the manufacture of lath of the character referred to have involved angular displacement of the strands as an incident to the expansion of the slitted blanks. Such displacement increases substantially the size of the openings defined by the strands as the latter are caused to assume positions which are edgewise with respect to'the plane of the sheet. The relative large size of the openings and the angularity of the strands have the objection that only a slight resistance is offered to the passage of plaster through the openings. Hence, in order to avoid the waste which would otherwise occur, it has been the practice to apply the plaster in coats, the initial or scratch coat being relatively thin and having as its primary purpose the filling of the openings to prevent passage through them of the material of the subsequently applied heavy or browning coat.

The principal object of the present invention is to overcome the above objection, this object contemplating a lath characterized by a strand arrangement which will render a scratch coat unnecessary and enable a substantial saving in plaster and in the time required to apply the latter.

A further object is to provide a lath having a substantial measure of stiffness.

A still further object is a process suitable for producing the lath described which can be carried out rapidly and with apparatus of simple design.

The invention is illustrated in the accompanying drawing in which:

Figure 1 is a plan view of apparatus suitable for practicing the process.

Figure 2 is a side elevation of the apparatus.

Figures 3, 4 and 5 are enlarged views taken along lines 34, 4-4 and 5--5, respectively, of Figure 1.

Figure 6 is a fragmentary view in plan of the iinal product.

Figure '1 is an enlarged section taken along line 1-1 of Figure 6.

Figure 8 is an enlarged fragmentary view in plan of the final product.

In carrying out the process a sheet ID of suitable gauge is passed through a pair of slitting rolls II and I2 intwhich it is formed with parallel longitudinally extending rows of slits. The latter provide strands l 3 which are connected by extensions I30. and bonds it, the slits l5 of alternate shaped to provide" annularjflutesIFWhichcOrre spond in number to 'tliefstrandsi'ii. and the other of which is formed'withfmating embossments'20.'f The crests of the flutes 19 engage thelineai' portions of 'the sheetf whi'ch includethelongslits while the embossmen'tsfzoforce the'longitudinally extending zones "between the long slitsinto the flutes. The strands l3, and the connecting portions containing the short slitsare thereby arched the long slits are 'formed in the bonds" ll.

Upon emerging from the forming rolls the sheet is expanded to the desired width, preferably by the application of forces which act parallel to the plane of the sheet. This is in accordance with conventional practice and apparatus of standard design (not shown) may, therefore, be employed. As the sheet is stretched in the manner described. the bond sections at the opposite sides of the creases 2| fold and the strand extensions at the opposite sides of the short slits pivot away from one another and bend at their points of juncture with the strands and bonds, the angular displacement of the extensions being supplemental to, and hence being facilitated by, the original small displacement effected by the forming rolls. The extensions at each end of each strand turn in opposite directions. Hence. in so far as any twisting effect upon the strand is concerned, counterwhile median creases 2| "whichare collinear'with j,

- act one another. As a result the strands maintain their flatwise positions in the sheet as the latter is expanded.

From the foregoing it will be apparent that the lath produced in accordance with the invention is characterized by strands which are arranged flatwise in the plane of the sheet. The lath has the advantage, therefore, that while it may be expanded to the same degree as conventional diamond mesh lath, the distance between strands is substantially less, so much so that the necessity of a scratch coat is avoided. In this connection it will be noted that the only parts of the sheet presented edgewise are the bonds and the strand extensions, that is to say those The slitting oi the blank and the pre-shaping oi the strands and connecting bonds are performed by rolls in a continuous operation. The process has the advantage, therefore, that it enables high speed production with apparatus of simple design. The arching oi the strands not only insures angular displacement of the extensaid strands and crease said bonds along median lines and expanding the sheet to fold said bonds along said median lines and deflect said extensions toward edgewise positions and bend them at their points of juncture with said strands and bonds, whereby to effect separation of the strands sions in the proper direction but also has the fur-'- ther advantage that a substantial measure of stifiness is imparted to the sheet.

I claim as my invention:

1. The method of producing metal lath and the like which comprises slitting a sheet to provide parallel rows of strands connected by strand extensions and bonds and expanding the sheet to deflect said extensions toward edgewise positions and bend them at their points 01' juncture with said strands and bonds, whereby to eflect separation of the strands while maintaining them substantially in their flatwise arrangement.

2. The method of producing metal lath and the like which comprises slitting a sheet to provide parallel rows of strands connected by strand extensions and bonds and expanding the sheet to fold companion sections of said bonds upon one another and deflect said extensions toward edge-,

wise positions and bend them at their points of juncture with said strands and bonds, whereby to effect separation of the strands while maintaining them substantially in their fiatwise arrangement.

3. The method of producing metal lath and the like which comprises slitting a sheet to provide parallel rows of strands connected by strand extensions and bonds, rolling the sheet to arch while .maintaining them substantially in their flatwise arrangement. p

4. The method of producing metal lath and the like which comprises slitting a sheet to form parallel rows of slits, the slits of alternate rows being in staggered relation with respect to the slits of intermediate .rows and being shorter than the latter, whereby to provide parallel rows of strands connected by strand extensions and bonds and expanding the sheet to deform said extensions and eifect separation of the strands while maintaining them substantially in their flatwise arrangement.

5. The method of producing metal lath and the like which comprises slitting a sheet to form parallel rows of slits, the slits of alternate rows being in staggered relation'with respect to the slits of intermediate rows and being shorter than the latter, whereby to provide parallel rows of strands connected by strand extensions and bonds, rolling the sheet to arch said strands and crease said bonds along median lines and expanding the sheet to fold said bonds along said median lines and deflect said extensions toward edgewise positions and bend them at their points of juncture-with said strands and bonds, to thereby efiect separation of the strands while maintaining them substantially in their fiatwise'arrangement.

' HARVEY M. GERSMAN. 

